Carton blank



FIG. 1 is a top plan view of a carton blank showing my new design;

FIG. 2 is a right side elevation thereof, the left side elevation being a mirror image;

FIG. 3 is a front elevation thereof;

FIG. 4 is a rear side elevation thereof; and

FIG. 5 is a bottom plan view thereof.

The solid lines in the top and bottom plan views represent cut lines in the blank structure and the dashed lines in the top plan view represent fold lines. 

The ornamental design for a carton blank, as shown and described. 